Warm & Humid Today

This year’s hurricane season has been strangely quiet both in the Atlantic and Pacific oceans. We have Hurricane Dora chugging along 15N in the Pacific which will miss the Hawaiian islands well to the south and that is it.  So far this year, discussions of our oceans and climate have largely focused on the onset of El Niño, recently declared by the World Meteorological Organization and its potential for pushing global temperatures into “uncharted territory” by the end of 2023 and into 2024. But in fact, we have already entered uncharted territory due to the exceptionally warm conditions in the North Atlantic Ocean.  Weak surface winds have put a damper on hurricane formation but I can’t help but wonder when the other shoe will drop.

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The weather should remain quiet in SW Michigan today, any rain in the state should be well north into the US10 corridor.  There is a slight chance of showers overnight near and east of US131 in our area (see forecast discussion).

Our next good chance of rain comes late Sunday into Monday when a heavy rain event may be in store.

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Grand Rapids Forecast

[pdf-embedder url=”https://michigan-weather-center.org/wp-content/uploads/2023/08/8-3-grr.pdf” title=”8 3 grr”]

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U.S.A and Global Events for August 3rd

1970: Hurricane Celia was the costliest tropical cyclone in Texas history until Hurricane Alicia in 1983. Hurricane Celia made landfall near Port Aransas as a major Hurricane, Category 3 on the Saffir-Simpson scale with sustained winds of 130 mph.

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Forecast Discussion

.SHORT TERM...(Today through Friday)
Issued at 348 AM EDT Thu Aug 3 2023

Surface cold front will sink slowly south through the state today
and tonight. A warm and humid air mass ahead of the front with
dew pts in the 60s will support SBCapes of 1000-2000 J/KG across
central and northern lwr MI this afternoon.

Guidance is highlighting northeast lwr MI and the Thumb, as well
as northeast WI and nrn Lk MI, for "best" coverage of convection
later today-- where decent low level convergence will exist.
Meanwhile a divergent low level flow in wrn lwr MI as well as
lingering dry air aloft will result in generally dry, warm/humid
conditions prevailing over majority of our area today.

Seems like our main risk of any showers/storms, if there is one,
comes tonight between 00Z and 06Z mainly near/west of Hwy 131 as
the remnant convection over northeast WI and nrn Lk MI activity
slips southward down Lk MI and the adjacent coastal counties. CAMs
are not in great agreement, but both the HRRR and NAM do support
this scenario.

An isolated shower/storm risk may linger into the overnight hours
before fropa, but the front is expected to clear the entire area
by 12Z Friday. Dry northerly flow in its wake delivers sunny and
pleasant conditions for Friday.


.LONG TERM...(Friday night through Wednesday)
Issued at 348 AM EDT Thu Aug 3 2023

- Heavy rain Sunday evening into Monday, strong storms -

Our chief concern for this timeframe is gradually pivoting away from
severe convection and towards heavy rain. Ensemble membership for
precipitation during this time is now nearly 100 percent. Rainfall
amounts continue to impress; WPC Weather in Context guidance notes
that daily rainfall records for several stations along and south of
the I-96 corridor are in jeopardy of being broken according to
deterministic NBM/NDFD guidance. Moreover, NBM probabilistic
guidance shows a roughly 20 percent chance of exceeding 2 inches of
precipitation between 8 PM Sunday and 8 AM Monday alone...and that
doesn`t include the additional, potentially substantial,
precipitation expected to occur into Monday night.

Strong to severe storms can`t be ruled out entirely. As noted
before, there remains a lot of temporal uncertainty regarding
instability and shear, both of which may end up bleeding into Monday
morning. This of course would have implications for timing, extent,
mode, and intensity of any thunderstorms that develop.

- Strong gusty winds accompanying the system Sunday and Monday  -

No changes to previous thinking. Impacts over land should be
minimal, but our marine zones and immediate lakeshore should feel
the brunt a bit more, especially Monday. Large waves are expected to
develop and beach conditions undoubtedly will become hazardous
thanks to efficient wave growth through nominal cold advection over
a warm lake.